It is known for a film cartridge to have a film exposure status indicator for providing a visual indication that a filmstrip inside the cartridge housing has been exposed. Often, the film exposure status indicator is one which cannot be used with a conventional type cartridge, but instead requires a special or new cartridge.
For example, prior art U.S. Pat. No. 5,278,600, issued Jan. 11, 1994, discloses an atypical film cartridge comprising a film spool rotatable inside the cartridge housing, an indicator window in an end cap of the cartridge housing, an annular indicator wheel rotatable inside the cartridge housing behind the indicator window to move a film exposed indication on the indicator wheel to the indication window, and an annular drive wheel rotatably linked with the film spool for rotating the indicator wheel to move the film exposed indication to the indication window. A pin and receiver clutch device transmits movement of the drive wheel to the indicator wheel when the film spool is rotated in a film unwinding direction, and leaves the indicator wheel and the drive wheel disconnected when the film spool is rotated in a film winding direction. Since the indicator wheel is located inside the cartridge housing, it cannot be used with a conventional type cartridge.
Another example is prior art U.S. Pat. No. 5,153,627 issued Oct. 6, 1992 which discloses an atypical film cartridge comprising a cartridge housing, a film spool rotatable inside the cartridge housing in film unwinding and rewinding directions, and a first indicator integrally formed with the cartridge housing and a second indicator secured to the film spool in order that the first indicator at least partially obscures the second indicator to provide an unused film indication when the film spool is rotated in the film unwinding direction and which are positionally reversed in response to spool rotation in the film rewinding direction for the second indicator to at least partially obscure the first indicator to provide a used film indication. Since the first indicator is integrally formed with the cartridge housing, it cannot be used with a conventional type cartridge.
The Cross-Referenced Application
The cross-referenced application discloses a film cartridge comprising a cartridge housing with a peripherally raised end cap which forms an open recess, a film spool rotatable inside the cartridge housing in film unwinding and rewinding directions and having a protruding spool end portion which coaxially projects from the cartridge housing into the recess, and a film exposure status indicator capable of changing state to provide a visual indication of the exposure status of a filmstrip for the film cartridge. A ring having a radial slit coaxially engages the protruding spool end portion in the recess to be rotated concurrently with the spool end portion in the film unwinding and rewinding directions. The film exposure status indicator is a flexible helix that is coiled around the protruding spool end portion in the recess and longitudinally extends through the radial slit in the ring. One end portion of the helix is fixed in place beneath the ring to be concealed from view and to prevent rotation of the helix when the ring is rotated with the film spool in the film unwinding and rewinding directions. A further portion of the helix is initially located above the ring to be visible and is adapted to be compressed beneath the ring to disappear from view responsive to movement of the radial slit along the further portion when the ring is rotated with the film spool in the film unwinding direction. This provides a change of state of the helix from being visible above the ring to being concealed beneath the ring. The ring and the helix are designed to fit as a unit on the protruding spool end portion and, therefore, can be used with a conventional type cartridge.